1. Field of the Invention
The present invention relates to a motor and a blower.
2. Description of the Related Art
In a motor including an armature, an electric drive current causes exciting vibrations in the armature. Moreover, the motor as a whole vibrates when a rotating portion of the motor is rotating. Such vibrations cause noise.
In recent years, with an increase in the number of electronic devices used in homes and workplaces, there has been a demand for reducing noise caused by various electronic devices, such as, for example, household electrical appliances and office automation appliances. Various techniques have been devised to reduce noise of motors, such as, for example, using inner-rotor motors and arranging as many parts of the motors as possible inside cases thereof. A known motor is described, for example, in JP-A 2013-99094.
However, it is difficult to prevent resonance of parts of a motor by simply arranging as many parts of the motor as possible inside a case of the motor. Accordingly, if the rotation rate of the motor is varied in a stepless manner, the rotation rate of the motor reaches a rotation rate which causes increased vibration due to resonance at some point, causing the motor to vibrate greatly.